In the manufacture of food emulsion products, e.g. sausage or frankfurters, a tubular food casing such as regenerated cellulose or collagen is loaded onto the stuffing horn of a filling machine and stuffed with the food emulsion. For example, where sausage and frankfurters are concerned the food emulsion would be comprised of emulsified meat together with fillers, seasoning, spices, etc. For such products, smaller size casing materials, for example, size codes 1 through 51/2 are used. Links are normally formed from the continuous encased extruded product, with the links, for example, being twisted at the separations between them or tied at those separations. Then the links are separated from each other, for example, by cutting the separations between ties. In the case of large diameter food emulsion products, such as bologna, cheese, salami and the like, the food emulsion is introduced into large, heavy-walled fibrous type casings or casings formed from thermoplastic films which, with the food emulsion stuffed therein, are formed into chubs or rather lengthy individual sticks. These large diameter sausage products are filled on stuffing machines comprising a meat pump and a delivery attachment in the form of a stuffing horn. The ends of this large code casing material are sealed with clips or caps, frequently also including means for hanging the end product, such as, for example, a looped string or a hook device. The large food emulsion products, such as bologna, etc., are frequently used to produce multi-slice packaged consumer products, and the stuffed products are usually packed in large "code" casings which, in the trade, are designated, for examples, Code No. 6 through Code No. 9.
The smaller sizes of stuffed food emulsion products in individual pieces, e.g., links, are typically then packaged with a predetermined number of pieces going into each package. High speed, automated packaging equipment is used to handle, transport and package the individual pieces and to seal and label the packages when filled. For customer appeal, and to maintain precisely consistent weights, package for package, each piece must be the same size, have the same material consistency and be the same weight as each other piece.
Many of the large food emulsion stuffed products, on the other hand, are sliced and packaged into units of predetermined weight and slice count for retail sale. High speed slicing devices are used in conjunction with such consumer packaging operations, with the overall system being designed to produce uniform and consistent packages of sliced food products with a predetermined weight and count yield. Thus, a very important consideration in the production of both smaller and larger stuffed food emulsion products is that the encased product have a substantially uniform diameter and density of material therein.
In stuffing casings, a sizing and/or braking system is typically employed for controlling casing expansion so as to avoid exceeding the casing specification, establish by the manufacturer, regarding the recommended stuffing diameter. Also the use of the sizing and/or braking system can inhibit back purge of food emulsion. A brake device usually applies uniform pressure to the exterior wall of the unfilled casing as it is being pulled from the stuffing horn by the food emulsion which is extruded through the horn into the casing. A sizing device, on the other hand, usually imposes some restriction on the extruding food emulsion at the point of, or just following, the exit of the food emulsion from the stuffing horn; for example, a sizing device may function to cause the casing to stretch out to its full, unwrinkled diameter.
The distinction between a braking device and a sizing device tends to be a very gray area in the trade and in many cases the terms are used interchangeably. Both devices, no matter what particular terminology is used, are designed to apply some sort of frictional limitation, holding back the otherwise free movement of the casing, from its shirred form on the stuffing horn, onto the extruded food emulsion. If the casing is not restricted, the food emulsion which is extruded will not be consistently densified and may not completely expand and fill the casing. In many combined brake/sizing systems, the design is such that forces are applied uniformly and circumferentially to the outer casing wall, forcing it against the stuffing horn, thus, creating friction between the inner casing wall and the stuffing horn and, respectively, between the outer casing wall and the brake/sizing system.
The stuffing cycle typically begins with the operator loading the precut length of casing onto the stuffing horn. The first end of the casing, that end which is first to be filled with food emulsion and the end which is last to be slipped over the stuffing horn, typically has an end-closure. The end-closure may be formed from a gathering together of the end casing material with that gathering, typically, then being tied or clipped; there may also be a loop or tie string attached to the end-closure. The closed first end of the casing is brought flush with the outlet end of the horn. Then the horn and the brake/sizing system are aligned, usually axially, and the brake/sizing system assembly is fitted, sometimes forced, over the outer wall of the casing now on the horn, so that compressive forces are applied to the casing, pushing it against the horn at a point adjacent to the outlet end of the horn.
As mentioned previously, an important consideration, in the production of food emulsion products, is the maintenance of accurate diametrical and circumferential size control over the entire length of the stuffed food emulsion product. It is particularly important that the diameter of the large products be carefully controlled so that the packers are able to cut the chub or stick into slices of predetermined thickness and diameter for consumer packaging. The objective is to have a given number of slices weigh precisely a predetermined amount for each package. On the other hand, the smaller diameter products require not only diametrical control, but length control as well to enable the production of uniform pieces or links.
When a casing is understuffed from the recommended "green" diameter specified by the casing manufacturer, the result generally is a processed product that is not uniform in diameter from end to end and piece to piece. (The "green" product is the food emulsion product after stuffing but before further processing.) When understuffed, the product is undesirably wrinkled in appearance and the food emulsion product may have an emulsion brake down yielding undesirable pockets of fat or liquid. On the other hand, when a casing is overstuffed from the recommended green diameter, the casing may split or break apart at the stuffing station or subsequently, in transport to or in subsequent cooking or smoking processing operations. This results in a costly waste of food emulsion and the labor expense for clean up. Where smaller diameter products are being produced, overstuffing can result in inconsistent piece lengths, causing subsequent packaging problems.
A variety of differing arrangements of braking and sizing devices have been used in the food emulsion stuffing operations practiced by the food packaging industry. For example, U.S. Pat. No. 4,709,450 and U.S. Pat. No. 4,773,128 show automated equipment for stuffing food casings to provide dimensionally uniform products, including braking/sizing devices as shown in FIG. 6 of both references. Each of these references shows apparatus which is particularly adapted to the stuffing of large code casings, and both apply a resilient sizing ring to maintain pressure on the casing as it traverses the cylindrical portion of the stuffing horn. As shown in both FIGS. 6 and FIGS. 7 of both references, elaborate mechanical means are required to hold the sizing ring in position and to maintain the pressure of the sizing ring against the cylindrical portion of the stuffing horn. Although such means function to expectations, both include many areas into which dirt and contamination can find their way. These areas are difficult to clean, and to maintain as clean, during the operation of the food emulsion stuffing equipment, resulting in potential safety and health concerns. Various other designs of braking and sizing apparatus are also employed in the industry many of which have the same potential safety and health concerns. Thus there is a need in the industry for means which diminish and/or eliminate these concerns, providing reassurance to both the industry and official regulatory agencies that the end product can be essentially contamination free.
One form of casing that is used in the industry is known as a "shirred" casing wherein the casing material is longitudinally compressed back upon itself in an accordion fold manner. Each length of shirred casing, which may be extended to, for example a length of about 100 meters, is compressed into lengths which may extend in length to only 20 cm. This is particularly true with shirred casing sticks used in the production of frankfurters as well as smaller size link sausage products. For the large code casings, the extended length can be much shorter, often less than a meter in length, and the shirred length for such casings may only be a few centimeters in length. Such short casings are typically used where a single casing strand is used to make only one green encased food emulsion product piece. Examples of such are found in those sausage products which are classified as dry cased sausage, such as pepperoni, summer sausage, hard salami and the like.
The shirred casing sticks are often prepackaged to maintain them in a shirred condition and to make the shirred sticks capable of being readily sheathed onto the stuffing horns of food emulsion stuffing equipment. One example of such a packaged shirred casing is shown by U.S. Pat. No. 4,484,679. In this reference there is shown a shirred casing stick which is prepackaged in a wrap sleeve. The wrap sleeve is formed from a tubular plastic section into which the shirred casing stick is inserted. The ends of the wrap sleeve extend beyond the ends of the shirred casing stick. These extended wrap sleeve sections are heated to the point of relaxation and compressed against the ends of the shirred casing stick by mechanical plungers while the plastic wrap sleeve material is in a fluid state at the elevated temperature. Such heat formability of a variety of plastic materials are well known to those with skill in the field. The packaging taught in U.S. Pat. No. 4,484,679 is merely that, simply a packaging; it includes no means for accomplishing any function other than simply holding the shirred casing stick in form and in a shirred condition.
U.S. Pat. No. 4,422,215 shows another form of packaging for a shirred casing stick. In addition to wrapping the shirred casing stick in plastic, this reference shows the inclusion of a "calibrated ring" which is included in the packaging at the lead end of the shirred casing stick to enhance the ability of the stick to be fitted over the tubular form of the stuffing horn. In U.S. Pat. No. 4,422,215, as was true for U.S. Pat. No. 4,484,679, there is, apparently, no thought given to any means other than those which function to package the shirred casing and to provide for the capability of the package, with the shirred casing in it, to be readily fitted over the tubular form of the stuffing horn of food emulsion packing equipment.
U.S. Pat. No. 4,007,761 shows yet another form of packaging for shirred casing sticks, again using a plastic material to enclose the shirred stick and to maintain it in its shirred form. This reference, in addition, shows the inclusion of a sizing ring adjacent to the lead end of the shirred casing stick and encased in plastic within the package. In the arrangement shown in U.S. Pat. No. 4,007,761, as the casing stick is withdrawn from the package, being pushed by the extruding food emulsion product moving through the stuffing horn, the moving casing is expanded around the outside diameter of the sizing ring which is within the package. Thus, pressure and friction are imposed on the interior walls of the casing material, by distention of that casing material, as it is pulled off of the shirred stick. The sizing ring is maintained in place at the lead end of the shirred casing stick by the plastic packaging which surrounds both the shirred casing stick and that sizing ring. According to the design shown in U.S. Pat. No. 4,007,761, the packaging need not be removed to place the combination of the shirred stick and the sizing ring onto the stuffing horn of a food emulsion pump apparatus. The sizing ring of U.S. Pat. No. 4,007,761 serves to expand the casing material to its full diameter, smoothing out the wrinkles therein, but provides relatively little regulation and restraint in regard to the rate at which the casing material may be pulled from the package. Thus, there is a concern that voids may be included in the food emulsion, which is extruded into such a casing, and that the consistency of the material extruded into that casing will not have sufficiently uniform density to provide the uniform weight which is necessary for both link and sliced products as described above.
The packaging described in U.S. Pat. No. 4,007,761 is a definite step in the right direction as it provides a package, with some means for sizing the casing material, which does not include the elaborate and complicated mechanical equipment as shown in U.S. Pat. No. 4,709,450 and U.S. Pat. No. 4,773,128. Thus the concern for contamination and build up of dirt is largely eliminated by this package. However, packaging is needed wherein sufficient frictional restraint can be readily imposed preferably on the exterior of the casing material as it is being pulled from the shirred casing stick, but without need for elaborate mechanical means for holding such a braking means in place or applying regulatory pressure to the braking means. An added advantage would be the inclusion of an integrated and simplified means for sizing the product being extruded.
As will be noted in U.S. Pat. No. 4,007,716, a clip or some other closure means, is used to form the end-closure of the lead end of the shirred casing stick. A variety of different plastic and/or metal clips are commonly used in the food emulsion packaging industry, variously with and without some sort of device, such as a string or a hook, to be utilized for hanging the sausage product. Such means for hanging the sausage may be necessary, for example, in the case where the sausage material is further processed, such as in the smoking operation and/or in further seasoning or aging processes as are frequently employed in the production of various types of stuffed food emulsion products. In particular, for dry cased sausage products, the casing material is usually moisture permeable and the products must be hung for some period of time to permit the gradual and slow escape of moisture from the package.